This example shows a zoomable and pannable world map with hover highlighting on individual countries. It renders geographic boundaries using `d3.geoPath` with a `geoNaturalEarth1` projection, drawing country shapes from TopoJSON data and matching country names from a TSV file. The map supports interactive zooming through D3's `zoom` behavior, which applies transformations to the SVG group element. Country polygons fill with steel blue, and hovering changes their fill to light blue via CSS.